Kansas City Royals owner Ewing Kauffman intends to sell almost half the stock in the club, according to a copyright story.

The Kansas City Star said Kauffman has signed a letter of intent to sell 49 percent in a $10 million transaction expected to be completed Wednesday and subject to American League approval. The purchaser would be Michael Shapiro, a former Kansas Citian now living in Los Angeles, backed by investors described by a Kansas City banker as "some pretty heavy hitters."

Added to the letter was a notation signed by Kauffman that the sale is subject to a satisfactory agreement on cable television, the Star reported. An additional $1 million is to be paid for the cable TV rights, with a contract set for 1983-90 . . .

New York Yankee Manager Billy Martin charged in Louisville that Commissioner Bowie Kuhn "didn't do his homework" when he banished Mickey Mantle from organized baseball last week for taking a public relations job with a casino.

"After he finds out why Mickey had to do it, he'll realize that Mickey didn't do anything to hurt baseball," Martin said of his old Yankee pal.

"Mickey's just doing four golf tournaments and the dollars were needed for other reasons." He said Kuhn should realize that "this isn't 1912, it's 1983" and "gambling (now) is right there out in the open."